In testing issue6727, I added a test (http://hg.python.org/cpython/rev/afe67ea94bc6) to the default branch. The test passes on Windows, but fails on some of the Unix buildbots. Here's a quick breakdown of where it's passing and failing:

The test is already present in test_import but is disabled because it is currently failing. I should mention that I believe this is a regression with 3.3 over 3.2. It is certainly a regression over 2.7.